Excimer laser its corneal shaping ability is particularly strong, very accurate, the excimer laser used for corneal shaping, it is equivalent to grinding a lens on the cornea, so that this technology its corrective effect is particularly ideal, so the excimer laser, and now it has become the main way to correct our vision.
Excimer laser surgery is suitable for the following groups of people:
1, 18 years of age or older
2, myopia stabilized for more than two years
3, the cornea is the right thickness
4, the eye is not inflammatory, such as acute conjunctival, inflammation keratitis
5, not in the active period of diabetes, hyperthyroidism
6. There are risks
5. Abuse of surgery is common, with complications such as decreased visual quality and infection
2. Intraocular Lens Surgery
Who is suitable for Intraocular Lens Surgery:
1. Patients between the ages of 18-45 years old
2. Patients with ultra-high myopia, i.e., myopia of more than 1200 degrees.
The advantages and disadvantages of intraocular lens:
1, keep the cornea intact, does not affect the appearance
2, after the operation to achieve the best corrective effect
3, the requirement of the preoperative refractive and ophthalmic examination of high precision
4, the doctor's surgical skills require a high degree of surgical therapy of myopia, the effect of its is certain, and satisfactory, but there are strict indications and The surgery is definitely effective and satisfactory, but there are strict indications and contraindications, not many people can take surgical treatment, after all, surgery is some kind of damage and injury to the eyes, accept myopic surgery treatment must be careful. There are many surgical methods to treat refractive error, which can be categorized into corneal surgery, scleral surgery and lens surgery. At present the more successful do more or corneal excimer laser surgery. The following is the most common excimer laser refractive keratomileusis (PRK) and excimer in situ keratomileusis (LASIK) indications, contraindications, complications related to the knowledge introduced to you. Excimer laser refractive keratectomy (PRK) Excimer laser (also known as PRK) is a new type of laser developed in the 70s, it is an excited dimer laser, also known as excited excimer laser, the active medium is an inert gas mixed with halogen molecules, the formation of extremely unstable compounds dimerized by the excitation of external energy, began to be used in ophthalmology in the early 80s. Wavelength of 193urn fluoride atmosphere (ArF) excimer laser has a short wavelength, high energy, short pulse, beam performance is good, high precision, good repeatability, with the excimer laser cutting tissue, neat incision, adjacent tissue damage is small, the damage area away from the cutting surface of less than 0.2pm, the intraocular tissues do not have any effect. According to the principle that the shorter the wavelength, the higher the photon energy, the smaller the range of thermal damage around the incision it accompanies, the 193urn excimer laser has almost no thermal damage. The excimer laser is also characterized by high cutting precision, shallow penetration depth < 0.3pm and high predictability. It is therefore most commonly used in laser keratomileusis. However, it also has certain disadvantages: ① As the wavelength of 193urn excimer laser is the peak of cellular DNA spectral absorption, so it has the potential danger of teratogenic mutation. ② Excimer laser working medium - ArF gas is a highly corrosive and toxic gas, any mechanical failure may cause gas leakage, resulting in environmental pollution, posing a danger to staff and patients. ③ Excimer laser is bulky, complex and expensive equipment, the application of excimer laser cutting corneal tissue, changing the curvature of the cornea, the pathology section after the operation shows neat junction, no obvious thermal damage to the surrounding tissues. Many countries in the world have carried out this kind of surgery and achieved satisfactory results in the treatment of myopia. China has introduced this technology since 1992, and has carried out this work in many cities one after another with good results. Excimer laser PRK is accepted by patients for its advantages of good predictability, stable effect and few complications. ① Preoperative examination: Ask for a detailed medical history and find out whether there are eye complications and systemic contraindications that affect the surgery. ② Ocular examination: a. Routine ophthalmologic examination: visual function examination, routine examination of the anterior eye, refractive examination, slit lamp examination, fundus examination, intraocular pressure examination, flushing the tear duct. b. Special examination: corneal curvature examination. b. Special examination: corneal curvature meter, ultrasonic corneal thickness gauge, corneal topographer, ocular B-type ultrasonography. ③ Systemic examination: a. General examination: temperature measurement, blood glucose, urine glucose examination is very necessary. b. Cardiac, renal, hepatic and pulmonary examinations: to exclude the whole body diseases that affect wound healing <?XML:NAMESPACE PREFIX = V /> <?XML:NAMESPACE PREFIX = O /> <?XML:NAMESPACE PREFIX = W /> to improve the tolerance of the operation and prevent accidents from occurring during the operation. and prevent intraoperative accidents.
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Respondent: Mr. Tang Ziqiang - 大士 十六级 6-17 15:26
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Other Answers *** 2 entries
The treatment of myopia can be categorized into surgical and non-surgical therapies.
(1) The best treatment for myopia - a proper pair of glasses.
The distance vision of myopic patients is reduced to varying degrees, so that they can't see the sights beyond a few meters, can't see the goods on display or the price tags in the shopping malls, can't recognize the acquaintances walking on the opposite side of the road, can't greet people, and are regarded as being ignored; and the students can't read the wrong problems on the blackboard and do the wrong assignments. All these things make myopic people suffer a lot. To get out of this hazy world, the only way is to wear glasses. However, there are some patients suffering from myopia, would rather not be able to see things in the distance, squinting
eyes anxious, but also unwilling to wear glasses. The reason is that it is inconvenient for young people to wear glasses, and they are afraid of touching and falling. Some people think that wearing glasses is not good-looking, and it is an obstacle to the instrument. Fear of wearing glasses after the more you wear the deeper the degree of glasses on the glasses will not be able to take off again, put the glasses in the pocket, only in the distance to see the wear. In fact, this is not correct. When you are nearsighted, you cannot see distant objects because the parallel light rays entering your eyes cannot be focused on the retina. Although it is clearer to see things at a close distance, it is easy to cause eye fatigue when your eyes are too close to the books when you are studying. Children with myopia, performance is not lively, on the subject of attention is not focused, can not see the blackboard learning performance decline, and sometimes can produce strabismus. If you wear a pair of appropriate myopia glasses, you can move the image in front of the retina backward, so that it falls exactly on the retina, so you can immediately see things clearly. This will bring great convenience to both work and study, so why not? As for wearing glasses is inconvenient and unattractive, these concerns should be dispelled, wearing glasses is to correct vision defects, reduce eye fatigue, wear some days to get used to it, there is nothing unattractive. Will myopia get deeper after wearing glasses? We say generally no. The development of myopia has nothing to do with wearing glasses. It is true that some people with myopia, since wearing glasses after a period of time myopia deepened, and have to re-open the optometry, this is why? Some people think everything is fine after glasses, writing or reading books, still very close, do not pay attention to vision hygiene, reading time is too long, or lying down to read books or walk to read books or read books in places with insufficient lighting, etc., for a long time, the same lead to visual fatigue, myopia is increasing. Some young people take wearing glasses as a kind of burden, wear them for a while, don't wear them for a while, wear them when they are happy, don't wear them when they are not happy, or wear them when they look at the distance only, so that their eyes are often in an unstable state of adjustment, which will also make myopia deepen gradually. Some people do not go through dilated optometry or the optometrist is not experienced enough to make the glasses not suitable. Some people just buy a pair of glasses in the store or take other people's glasses to wear, even after wearing a mirror sometimes can barely see, but can not last, a long time the eyes will feel sore and uncomfortable. Not only can not improve vision, but will make myopia deepen. Therefore, myopic people, must go to the hospital dilated optometry or ask experienced optometrists optometry, with a pair of appropriate glasses, in addition to sleep and wash your face, all day and night to wear. Remember to never blindly borrow someone else's glasses.
How can I get an accurate, comfortable pair of glasses?
Young people suffering from myopia should always go to the hospital to have their vision checked and have their eyes dilated. Pupil dilation is also known as objective optometry, is the application of drugs (such as 2% after Matropine, 1% atropine eye drops, etc.), so that the ciliary muscle is completely paralyzed, the pupil dilated, the loss of regulation of the situation for optometry. In this way, the interfering influence of regulation and the pseudomyopia component caused by it are excluded, and the refractive state of the eye is determined objectively and accurately. Then, according to the eyeglass prescription determined by the optometry, the eyeglass lenses are sharpened, and the sharpened lenses are mounted on the eyeglass frames selected in advance. Usually, a retest is performed at a certain time after the dilated eye examination. Observe the refractive power of the objective optometry test lenses to wear with or without dizziness, nausea, blurred vision, vision distortion or walking unsteady and other abnormal discomfort. Through retesting, organically combining the objective dilated optometry results with the subjective post-test results in a consistent manner to maximize the high quality of eyeglasses fitting, so as to achieve the effect of the best correction of visual acuity.
Some young people are reluctant to have their eyes dilated for fear that they will feel uncomfortable and not be able to see the near things. In fact, this worry is superfluous. Pharmacology of dilated pupil optometry used in drugs (such as atropine, post-matropine, etc.) for the anticholinergic drugs. Its role in the pupil dilation muscle and ciliary muscle paralysis and relaxation, manifested as pupil dilation and regulation of paralysis, the role of this drug is only temporary, as long as no longer continue to use, after a certain period of time, the paralytic effect of the drug will naturally disappear. If you don't use dilated optometry, due to the ciliary muscle, lens regulation, may be tested too large or pseudomyopia results, so, young myopia should be dilated optometry, selection of appropriate myopia glasses. Only when the following conditions exist:
(1) Examination found shallow anterior chamber, high intraocular pressure or the high limit of normal value, suspected of glaucoma patients, should wait for a detailed history, a clear diagnosis before optometry. The application of dilated optometry is absolutely contraindicated in patients with glaucoma.
(2) Severe lens, vitreous clouding, corneal leukoplakia, due to the difficulty of examination, dilated optometry is meaningless.
(3) Severe pupillary adhesion, the pupil can not be normally dilated even after the application of dilating drugs, there is no need to dilate the pupil optometry.
(4) People over the age of 40, due to the weakening of the ciliary muscle regulation, generally no longer dilated optometry.
Currently, the main material for making eyeglass lenses is optical glass, also called optical eyeglass lenses. In addition, there are optical resin eyeglass lenses.
Optical glass has the following advantages
(1) high transmittance transmittance of up to 92%, if the surface of the lens coated with one or more layers of magnesium fluoride transmittance film, the lens transmittance of up to 99.2%.
(2)Absorb ultraviolet rays Avoid ultraviolet damage to the eyes.
(3)Chemical stability Resistant to acid, alkali and other chemicals.
(4)Constant and accurate refractive index The refractive index is 1.523, constant and accurate, and the refractive index is accurate after processing.
Optical resin is characterized by light weight, hardness close to glass, refractive index of 1.490, the new high refractive index thermosetting resin refractive index of 1.600, the surface is coated with a super-hard film and non-reflective multi-layer film to enhance the abrasion resistance, the transmittance of up to 98% and can block ultraviolet rays. Ground by the optical resin spectacle lenses, not easy to break damage to the eyeballs, security, has been widely used. Crystal material hard wear-resistant adiabatic good, but the ultraviolet absorption performance is worse than optical glass, light transmission is also poor, is not the production of spectacle lenses of the ideal material, not to mention the eye of the best products.
The processing of spectacle lens layer luminosity must be precise, grinding into a mirror to be consistent with the prescription, the error of refraction should not exceed 0.04D-0.09D of the Ministry of Light Industry, Ministry of the Ministry of the standard. The distance between the optical center of the two spectacle lenses and the distance between the pupils of the two eyes should also be consistent.
What we see and wear everyday are glasses that are set on the bridge of the nose or clamped on the ears, which is very inconvenient. There are also people who have a large degree of myopia in one eye and a small degree in the other, or who have cataract surgery in one eye and a normal eye in the other. Due to the refractive error of the two eyes is too large, one eye to see something big, the other eye to see something too small, the visual center can not blend them together, therefore, ordinary glasses can not be worn. In recent years, a type of eyeglasses that are worn but not visible, commonly known as contact lenses, has emerged. It is a lens that is worn directly on the surface of the tear layer of the cornea, and between the cornea and the lens there exists a liquid lens composed of tears. In this way, a new refractive system is formed by the lens, the liquid lens, the cornea and other refractive interstitium of the eye. In medicine, it is called corneal contact lenses.
Contact lenses can be categorized into hard contact lenses and soft contact lenses according to the material of the lenses. Hard contact lenses are made of methacrylate-based plexiglass, which is hard and not easily deformed. It is suitable for correcting high astigmatism and conical cornea. Its disadvantage is that it is not breathable, cannot permeate oxygen, carbon dioxide, water and metabolic substances, and is not very comfortable to wear. Soft contact lenses are made of hydroxyacetic acid methacrylate or silicone rubber, which are soft, breathable and can absorb water, soft and comfortable to wear, and can be used to treat corneal diseases, but they are easy to change shape and are not suitable for astigmatic eyes.
There are two types of contact lenses: long-wearing and daily-wearing. Contact lenses that are worn overnight for more than two consecutive days are long-wearing, including weekly, monthly, and even no-detachment types. Long-wearing lenses are worn for many days before being removed and cleaned once. Tear fluid proteins and other substances are deposited on the lenses, and permanent cloudy spots eventually occur, affecting the clarity of the lenses. More serious is the breeding of bacteria, it is very easy to occur infectious keratitis, in view of this, at present, the long wearing way is not advocated. Daily wear type continuous wear no more than 14 small
hours, every night must be removed for the necessary cleaning, disinfection and proper preservation, to this day to wear again. Since the daily wearer removes the lenses each night for cleaning, the lenses will not develop permanent cloudy spots. With daily cleaning and disinfection, the likelihood of infectious keratitis is greatly reduced. Therefore, daily wear must be adhered to and long wear is not advisable. Contact lenses have advantages that ordinary glasses do not have and solve problems that ordinary glasses cannot solve. Since contact lenses are closely adsorbed with the cornea and can be rotated with the rotation of the eyeball, no matter which direction the eyeball turns to, the light always enters the eye through the center of the lens, which eliminates the defects of prismatic effect and oblique astigmatism produced by the rim of ordinary eyeglasses. Contact lenses are ground according to the patient's corneal surface curvature and refractive index, it is tightly attached to the cornea, so that the lens, the tear layer and the cornea form a new refractive interstitial, involved in the composition of a complete optical unit, the curvature of the surface of the lens can be arbitrarily ground according to the refractive requirements. It replaces the irregular curvature of the corneal surface, effectively eliminates corneal irregular astigmatism, and reduces the disparity in the size of the object image between the two eyes. As contact lenses are close to the cornea, the distance from the center of the eyeball is shortened, and after the light passes through, the image formed on the retina is more or less the same as when you don't wear lenses, and you won't magnify or reduce the size of the object when you look at it. It avoids the shortcomings of ordinary glasses and is most suitable for people with large refractive error in both eyes or people without crystal in one eye. Contact lenses are thin and light, adsorbed on the surface of the cornea, which is much more convenient than the thick and heavy lenses of high myopia glasses. In addition, they are very convenient for people with special needs (e.g. actors, athletes). It is because contact lenses have so many advantages that ordinary glasses do not have, so its application range is much wider than ordinary glasses. Contact lenses are more suitable for people with the following conditions:
(1) High myopia, refractive error of more than 3.00D in both eyes, mixed corneal astigmatism or irregular astigmatism. In particular, some literary or sports workers, due to the needs of the profession, wearing ordinary glasses will affect the work or competition results, can choose to use contact lenses.
(2) Some people who have had cataract surgery on one eye can only wear contact lenses because the refractive error is too large to wear ordinary glasses.
(3) Soft contact lenses can be used to treat corneal edema, exposure keratitis, and dry keratoconjunctivitis. Coating the periphery of the lens with the same color as the iris and keeping the central part transparent can eliminate the symptoms of photophobia in patients with albinism and iris defects. In recent years, there are specially made for therapeutic purposes and corneal contact lenses, contact lenses immersed in some kind of drug, can be released to the conjunctival sac at regular intervals, which not only reduces the number of times the drug is ordered, saving the amount of medicine, while the conjunctival sac can always maintain a higher concentration of the drug, to achieve better therapeutic effects, such as the treatment of glaucoma, corneal ulcers, and so on.
While contact lenses have a number of advantages, however, they also have certain limitations and are not suitable for everyone. There are three contraindications to contact lens wear.
*Our own conditions Eyelid inversion and inverted eyelashes, incomplete closure, dacryocystitis, dry eye, severe trachoma and chronic conjunctivitis, keratitis, diabetes, hypertension, paranasal sinusitis and so on.
*Environmental conditions Wind and sand, dust, volatile chemicals and severely polluted environments.
*Personal qualities Poor hygiene habits, poor self-care and inability to adhere to serious caregivers, such as primary and secondary school students.
Although contact lenses are constantly being improved, their chemical properties, comfort and safety have all reached a more desirable level and are more widely used. With the popularization of the application and long time clinical observation, there are some complications of varying degrees of severity. Such as corneal injury, conjunctival inflammation, corneal infection.
How many years, the cure of myopia, remove glasses, become the majority of myopia and wear glasses due to myopia people's urgent wish, looking forward to the nemesis of myopia and the arrival of the gospel, to round off a dream of removing glasses. It is in this case, some cater to parents and young people eager to remove glasses of the psychological, so that the so-called effective rate of up to 95% or more of the therapeutic appliances and drugs will continue to come into being.
The methods that have been tried and tested to treat myopia include acupuncture, plum blossom needle method, auricular acupuncture, electro-acupuncture, low-frequency current method, ultrasonic method and acupoint laser irradiation method, etc. These therapies are very effective in preventing myopia. These therapies are effective in the prevention of myopia and the treatment of pseudomyopia, but they are not effective in the treatment of true myopia. In recent years, countless medical personnel engaged in ophthalmology and pharmacy experts have conducted useful research on the treatment of myopia, and formulated some medicines for the treatment of myopia, such as summer no eyedrops, 1% dibazole eyedrops,
Danshen eyedrops, safflower eyedrops, myopic eye 1, 2 eyedrops, etc. These eyedrops can be effective to a certain extent in the prevention of myopia and the treatment of pseudomyopia, but have no definite effect on the true myopia. These eye drops can relieve ciliary muscle spasm to a certain extent, and have a certain effect on mild myopia, especially adolescent myopia and pseudomyopia. The visual acuity of a part of patients can be improved, but the efficacy is not consolidated. In short, the effect of drug treatment of myopia is not satisfactory at present. As for the magnetic therapy glasses, vision care instrument, vision care device, vision correction instrument, physical therapy mirror, eye mask, mirror and other myopia treatment apparatus can be described as a variety of varieties
More than one, advertisements are frequently seen in a variety of publicity media, the advertisement is extremely exaggerated, and even more so, some of them are also crowned with the National Patent, is very tempting. So many people with a try to see the psychological fall a ride money and ride time, and finally have to wear glasses.
(2) Surgical treatment of myopia
Indications for surgical treatment of myopia: age of 18 years or older; myopic refraction of 2.50D or more; normal vision corrected by wearing glasses; the need to remove glasses; cornea without active lesions or conical cornea; no history of diabetes or collagenous diseases.
As mentioned earlier, myopia can be treated with acupuncture, medication, and other methods, but the more definitive and reliable treatment is still wearing myopia glasses. However, both framed glasses and contact lenses have their shortcomings that are difficult to overcome. Is it possible to use surgery to correct vision? In the 1980s, some advanced countries in the world successively carried out the surgical treatment of myopia - radial keratotomy, or PRK for short, which originated in Japan, and then ophthalmologists from the former Soviet Union and the United States improved and perfected the surgical method and equipment so that the accuracy of radial keratotomy was greatly improved. The accuracy of radial keratotomy has been greatly improved, and a large amount of clinical experience has been accumulated to achieve a better therapeutic effect. Especially for young adults over 20 years old, the success rate of the surgery for mild and moderate myopia is over 95%, and for high myopia of 6.00D-10.00D, most of the glasses can be removed, and for high myopia of more than 10.00D, the myopia can be reduced. It is also effective for myopic astigmatism. Radial keratotomy has opened up a new way for the treatment of myopia. China's myopia surgery is carried out late, about the mid-80s, radial keratotomy to China, it will be popular all over the country, large and small hospitals have to hang on, including the Russian foreigners invited to the knife. Due to the lack of surgical instruments and insufficient clinical experience, the postoperative corrected vision was less than ideal and there were many complications. In recent years, some large hospitals in China have purchased advanced foreign surgical instruments - gold diamond knife. This kind of knife is not only sharp, and the blade is thin (only 0.1 millimeters), and there is a scale display, you can adjust the depth of the incision. The postoperative corneal scar is fine, uniform in width and depth, and has less chance of causing irregular astigmatism. Therefore, it is very popular among myopic patients, especially those with high myopia.
In addition to radial keratotomy, many new methods of surgical treatment of myopia have appeared abroad, and these surgeries have been carried out in certain major hospitals in China.
(1)Surface Keratoscopy: Using allogeneic cornea, different refractive errors are ground out on a special machine tool after cryoprocessing, and then the central part of the patient's cornea is separated from the lamina propria, and a special corneal lens is embedded into the lamina propria, and sutured around it, to achieve the purpose of correcting myopia.
(2)Keratomileusis: Using one's own cornea, the central part of the patient's cornea is laminectomized, the corneal tissue is cryogenically treated to harden it, and then ground on a fine lathe as needed to achieve the desired refractive error, and then sewn back to the original place.
(3) Laser Keratotomy: The excimer laser (wavelength of 193 millimeters) is used to make a radial keratotomy. It makes the incision more delicate, accurate, better corrective effect, and greatly reduces the surgical complications.
(4) Posterior Scleral Reinforcement: This surgery applies medical silicone sponge, allograft sclera or broad fascia as protective reinforcement material, reinforces and fuses the posterior pole sclera, supports the posterior pole of the eye, stops the progressive expansion of the posterior pole and the progressive lengthening of the eye axis,
reduces the myopia to a certain extent. At the same time, neovascularization is formed after the surgery, which enhances the blood circulation in the choroid and retina, excites the optic cells, activates bioelectricity, and improves visual sensitivity. This procedure is suitable for controlling the progressive lengthening of the eye axis in high myopia, especially important for adolescents with high myopia whose eye axis length is more than 26 millimeters and whose myopic refractive error deepens and develops more than 1.00D per year.
Surgical complications Myopia surgery has been welcomed by myopic patients as it solves the problem of wearing glasses for high myopia to a certain extent, and also meets the needs of people working in special occupations. However, no matter how simple and safe the surgery is, it is by no means foolproof. Moreover, myopic surgery is not a very mature surgery, and many aspects of the surgery still need to be improved. Currently, the main surgical complications are:
(1) intraoperative corneal perforation complicating cataract and bacterial endophthalmitis;
(2) corneal ulcers, delayed healing of the incision and damage to the corneal endothelium;
(3) postoperative scarring and epithelial cysts causing irregular astigmatism, which can seriously affect visual acuity;
(4) residual myopia, refractive error, astigmatism, or overcorrection. Excessive
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